SSL Certificate Details in UIWebView - ios

Question

I need to show SSL certificate details of displayed URL in a UIWebView something like Google's Chrome browser shows:
How to obtain this data from UIWebView.

Answer 1

We are intercepting the call at the network level (rather than the UIWebView), and using [NSURLConnectionDelegate connection:willSendRequestForAuthenticationChallenge:]. This gives you a NSURLAuthenticationChallenge instance, and if challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust then NSURLAuthenticationChallenge.protectionSpace.serverTrust is a SecTrustRef.
Given the SecTrustRef, you can follow SecCertificateRef: How to get the certificate information? and do something like this:
#import <Security/Security.h>
#import <openssl/x509.h>
X509* X509CertificateFromSecTrust(SecTrustRef trust) {
SecCertificateRef cert = SecTrustGetCertificateAtIndex(trust, 0);
CFDataRef certDataRef = SecCertificateCopyData(cert);
NSData *certData = (__bridge NSData *)certDataRef;
const void* certDataBytes = certData.bytes;
X509* result = d2i_X509(NULL, (const unsigned char**)&certDataBytes, certData.length);
CFRelease(certDataRef);
return result;
}
static NSString* X509NameField(X509_NAME* name, char* key) {
if (name == NULL)
return nil;
int nid = OBJ_txt2nid(key);
int index = X509_NAME_get_index_by_NID(name, nid, -1);
X509_NAME_ENTRY *nameEntry = X509_NAME_get_entry(name, index);
if (nameEntry == NULL)
return nil;
ASN1_STRING *nameASN1 = X509_NAME_ENTRY_get_data(nameEntry);
if (nameASN1 == NULL)
return nil;
unsigned char *issuerName = ASN1_STRING_data(nameASN1);
return [NSString stringWithUTF8String:(char *)issuerName];
}
NSString* X509CertificateGetSubjectCommonName(X509* cert) {
if (cert == NULL)
return nil;
X509_NAME *subjectName = X509_get_subject_name(cert);
return X509NameField(subjectName, "CN"); // Common name.
}
NSString* X509CertificateGetIssuerName(X509* certX509) {
if (certX509 == NULL)
return nil;
X509_NAME *issuerX509Name = X509_get_issuer_name(certX509);
if (issuerX509Name == NULL)
return nil;
return X509NameField(issuerX509Name, "O"); // organization
}
This is not a simple piece of work. You'll need to understand OpenSSL's X509 code, the Security framework, and whatever you're doing at the network layer for SSL trust checks. There might be other ways that you can get hold of a SecTrustRef or SecCertificateRef, but I'm not using them if there are.